/*
 * Copyright (c) 2011, okazoh_tk. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *  - Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 *  - Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 *  - Neither the name of the copyright holder nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include "./GLPrivate.h"
#include "./GLWriterDelegate.h"
#include "alkes/opengl/GLGraphics.h"

namespace alkes {

GLWriterDelegate::GLWriterDelegate(const Rect& target_rect, const Rect& rect)
: target_rect_(target_rect)
, rect_(rect)
{
}

GLWriterDelegate::~GLWriterDelegate()
{
}

void GLWriterDelegate::write(ImageWriter& writer, const PixelFormatTraits* traits, int32_t pitch, int32_t width, int32_t height)
{

#if !defined(ALKES_OGL_DISABLE_ReadBuffer)
    glReadBuffer(GL_FRONT);
#endif

    Rect::value_type gl_y = target_rect_.height - (rect_.y + rect_.height);

    GLenum gl_format = GL_RGBA;
    GLenum gl_type = GL_UNSIGNED_BYTE;
    uint8_t* pixels = (uint8_t*)alkes_malloc(pitch * height);

    if (pixels)
    {
        glReadPixels(rect_.x, gl_y, width, height, gl_format, gl_type, pixels);

        pixels += (pitch * (height - 1));
        int32_t y;
        for (y = 0; y < height; ++y, pixels -= pitch)
        {
            invokeWriteScanline(writer, traits, pixels, pitch, width, y + rect_.y);
        }

        alkes_free(pixels + pitch);
    }
}

}
